COVID-19 vaccine weekly safety report - 05-08-2021

The most common adverse effects reported to the TGA following immunisation are predictable and have been observed with vaccines generally. They include headache, muscle pain, fever, chills and injection site reactions.

The most common reactions reported for the AstraZeneca COVID-19 vaccine in the week of 26 July-1 August 2021 were headache, fever, muscle pain, joint pain and fatigue.

The most common reactions reported for the Comirnaty (Pfizer) COVID-19 vaccine in the week of 26 July-1 August 2021 were headache, fatigue, muscle pain, nausea and dizziness.

Interpreting information on vaccine adverse event reports

The TGA makes adverse event reports publicly available in the Database of Adverse Event Notifications (DAEN).

We encourage reporting of adverse events even if people are uncertain or only suspicious that it is related to a vaccine or if the event is related temporally, meaning symptoms occurred in a timeframe that suggested they could be linked to vaccination. Thus; the reports received by the TGA contain suspected adverse events that reflect the observations of the people reporting them. These observations are reviewed, coded and published in the DAEN irrespective of whether the adverse event is assessed by the TGA to be related to the vaccination. Publication of an adverse event report does not mean that the details of the event have been confirmed, or that the event has been determined to be related to the vaccine. Some events would have happened anyway, regardless of vaccination. This is particularly the case when millions of people are being vaccinated, and especially when vaccines are given to older people and those with underlying illnesses.

Reporting suspected adverse events supports our scientists and health professionals who use the data to look for new safety signals.  In some states the reporting of specific outcomes, such as death, that occur closely following a vaccination is mandatory for health professionals regardless of whether the vaccine was thought to be the cause For this reason, the number of adverse events and deaths reported is not the best indicator of the safety of the vaccines. The most authoritative safety information on the COVID-19 vaccines is included in the Product Information (PI) and Consumer Medicine Information (CMI) which can be found on the TGA website. 

When looking for information about COVID-19 vaccines, consider whether the source of the information is credible. Useful websites such as ‘COVID vaccines – is it true?’ can address false claims and misleading rumours. Other reliable resources are listed at the end of this report.

Latest immunisation recommendations

COVID-19 outbreak

As the COVID-19 outbreak involving the Delta variant continues to grow, the risk of contracting COVID-19 disease remains significant. Emerging data from the NSW outbreak indicates that vaccination protects people from infection and even in the small number of vaccinated people who become infected it significantly reduces the severity of disease.

Although Comirnaty (Pfizer) is preferred over the AstraZeneca vaccine for those aged 16-60 years old, the Australian Technical Advisory Group on Immunisation (ATAGI) has advised that in a large outbreak, the benefits of the AstraZeneca vaccine strongly outweigh the risk of rare vaccine side effects in all age groups. ATAGI reiterates that all adults in greater Sydney should strongly consider the benefits of earlier protection with COVID-19 Vaccine AstraZeneca rather than waiting for alternative vaccines.

Given the Delta strain seems to be more easily transmitted and possibly causes more severe disease, ATAGI reinforces the importance of reaching higher levels of first dose coverage as soon as possible. ATAGI also continues to recommend getting the second AstraZeneca dose within 4–8 weeks after the first dose, rather than waiting 12 weeks, so full protection can be reached sooner. For the Comirnaty (Pfizer) vaccine, the recommended interval between doses is 3–6 weeks.

Vaccination during pregnancy

The Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG) and ATAGI recommend immunisation with the Comirnaty (Pfizer) vaccine at all stages of pregnancy. This is due to the risk of complications from COVID disease for pregnant women and their unborn baby. To date, no serious pregnancy-related safety concerns have been identified with the Comirnaty vaccine. Pregnant women are encouraged to discuss the timing of vaccination with their health professional. More details are given on the RANZCOG website.

AstraZeneca COVID-19 vaccine

To 1 August 2021, approximately 6.8 million doses of the AstraZeneca have been administered in Australia. We continue to receive reports of suspected side effects to the vaccine. These are generally consistent with what is being observed internationally and most are expected side effects that resolve within a few days.

Thrombosis with thrombocytopenia syndrome (TTS)

TTS is a rare event involving serious blood clots with a low blood platelet count. It is triggered by the immune system’s response to the AstraZeneca vaccine and is different from other clotting conditions.

The latest rates of TTS in Australia were published in a statement from ATAGI on 28 July 2021.

While TTS is very rare, some people may have concerns that they can discuss with their doctor. ‘Weighing up the potential benefits against risk of harm from COVID-19 Vaccine AstraZeneca’ includes information to help people make informed decisions about vaccination.

TTS cases to date

Since last week’s report, a further 3 reports of blood clots and low blood platelets have been assessed as confirmed or probable TTS likely to be linked to the AstraZeneca vaccine (Table 1).  Sadly, one of the cases, a 34-year-old woman from NSW, died yesterday. The TGA extends its sincerest condolences to her family and loved ones. We are in close communication with NSW Health who are undertaking further investigation of this case.

Table 1: Newly confirmed and probable TTS cases for the week of 30 July – 5 August 2021‡

New confirmed TTS	New probable TTS
Two new cases: 34 and 51-year-old women from NSW	One new case: 67-year-old woman from Victoria

‡As previously reported, the TGA determines whether a report is likely to represent TTS by assessing cases against accepted criteria established by the UK’s Medicines and Healthcare products Regulatory Agency.

In addition to the new cases identified above, one case previously reported as probable was reclassified to confirmed. This takes the total Australian reports assessed as TTS following the AstraZeneca vaccine to 93 cases (57 confirmed, 36 probable) from approximately 6.8 million vaccine doses. 

When assessed against the criteria used by the US Centers for Disease Control and Prevention (CDC), fewer than half of the cases reported to TGA are classified as Tier 1 cases which tend to have more serious outcomes. Tier 1 cases involve clots in an unusual location, such as the brain or abdomen (Table 2). 

In Australia, severe cases of TTS appear to be more common in women in younger age groups. Nearly half of the TTS cases in women required treatment in intensive care. Cases meeting the criteria for Tier 1 were also twice as likely to occur in women compared to men. Five of the 6 deaths occurred in women aged 34, 48 (2 cases), 52 and 72-years-old. The other death was in a 44-year-old man.  

Table 2: Total confirmed and probable TTS cases to date by age and CDC classification

Age	Total cases	CDC classification†
				Tier 1	Tier 2	Not classified
<30 years	1	-	1	-
30-39	2	2	-	-
40-49	6	6	-	-
50-59	23	11	7	5
60-69	22	8	6	8
70-79	28	8	8	12
80+	11	3	4	4
All ages	93 (42 men, 51 women)	38	26	29

† The US CDC classification is defined as:

• Tier 1 = clots in an unusual location (such as the brain or abdomen) and a low platelet count with or without antibodies that activate platelets (anti-PF4 antibodies)

• Tier 2 = clots found in common locations (such as the leg or lungs) and a low platelet count and anti-PF4 antibodies

• Not classified = case does not meet the criteria for Tier 1 or Tier 2 (for example clots in common locations with low platelet count but no evidence of anti-PF4 antibodies).

Cases have most often occurred about 2 weeks after vaccination, although the time to onset (or diagnosis) has ranged from one to 54 days (Table 3). 

Table 3: Time to onset, treatment and outcomes for TTS cases*

Time to onset/ diagnosis (days)	Median (range)	12 (1-54)
Treated in ICU	At any point	29
	Currently	4
Outcome	Discharged	72
		In hospital	15
		Fatal	6

*Data is based on the most recent medical information available to the TGA

Immune thrombocytopenia (ITP)

The TGA is continuing to monitor reports of suspected ITP, a type of thrombocytopenia or low platelet count. It can occur when the immune system is activated, for example by a viral infection or vaccination, and mistakenly destroys platelets which help blood to clot. ITP has been reported with other vaccines and in many cases it is mild with up to a third of people having no symptoms at all, or only minor bruising. However, about 5% develop severe bleeding.

To 1 August 2021, the TGA has received 41 reports of suspected ITP following vaccination. These patients had an extremely low platelet count, and signs of thrombocytopenia including unusual bruising, a nosebleed and/or blood blisters in the mouth. These symptoms occurred in a timeframe that suggested they could be linked to vaccination and no other obvious cause was identified based on the information provided to TGA.

We encourage people to seek medical attention if they experience signs and symptoms that could suggest ITP, such as unusual skin bruising or clusters of small red or purple spots that do not lose their colour when pressed. Unusual bleeding is another sign, for example bleeding from the nose or mouth that is hard to stop, or blood in the urine or stools.

Guillain-Barre Syndrome (GBS)

The TGA has been closely monitoring reports of GBS since the beginning of the COVID-19 vaccine rollout as it has been associated with other types of immunisations such as influenza vaccines. To 1 August 2021, the TGA has received 66 reports mentioning GBS as a suspected adverse event in people who have received the AstraZeneca vaccine. So far, international regulators have been unable to establish a clear link between GBS and the AstraZeneca vaccine.

GBS is a rare immune disorder in which the body’s immune system attacks nerve cells. The causes are not fully understood, but it often follows a viral infection (such as influenza, cytomegalovirus and glandular fever) or gastroenteritis caused by a bacteria called Campylobacter jejuni. It has also been associated with COVID-19 infection. GBS causes nerve inflammation and can result in pain, numbness, muscle weakness and difficulty walking. It tends to affect both sides of the body. In many cases GBS resolves within months but can sometimes take up to 2 years.

We encourage people to seek medical attention if they experience symptoms that could suggest GBS as early medical care can reduce severity and improve outcomes. Symptoms to look out for include weakness and paralysis in the hands or feet that can progress to the chest and face over a few days or weeks.

Up-to-date information about the expected side effects of the AstraZeneca COVID-19 vaccine can be found in the Consumer Medicine Information (for consumers) and Product Information (for health professionals).

Comirnaty (Pfizer) vaccine

Provisional approval of the Comirnaty vaccine in Australia has recently been extended to include use in children aged 12–15 years old. This decision was made after careful evaluation of data from clinical trials supporting the safety and efficacy of the vaccine in this younger age group.

ATAGI recommends that children aged 12–15 years who have a higher risk of severe COVID-19 should be prioritised for vaccination. This includes children who are immuno-compromised and those with asthma, diabetes, obesity, cardiac and circulatory congenital anomalies, neuro developmental disorders, epilepsy or trisomy 21. Aboriginal and Torres Strait Islander children aged 12–15 years and children living in remote communities are also a priority.

Recommendations for other children in this age group will be made by ATAGI in the coming months following review of emerging data on the safety and effectiveness of COVID-19 vaccination from overseas programs. Updated recommendations will also take into account results of mathematical modelling to predict the impact of vaccinating adolescents on the population as a whole.

To 1 August 2021, approximately 5.6 million doses of the Comirnaty (Pfizer) have been administered in Australia. Reports of suspected side effects of the Comirnaty (Pfizer) vaccine received by the TGA are consistent with what has been observed in the clinical trials and by other medicine regulators overseas.

Myocarditis and pericarditis

A warning statement about myocarditis (inflammation of the heart) and pericarditis (inflammation of the membrane around the heart) has recently been added to the Consumer Medicine Information and Product Information for the Comirnaty vaccine.

The TGA continues to monitor reports of myocarditis and pericarditis. To 1 August 2021, we have received 111 cases of suspected myocarditis and/or pericarditis.

These rare effects on the heart typically occur within 14 days of vaccination, particularly after the second dose of Comirnaty (Pfizer) and more often in younger men. While cases are usually transient and resolve following rest, some patients require treatment in hospital. We encourage people to seek medical attention if they experience symptoms that could suggest myocarditis or pericarditis such as of chest pain, shortness of breath and palpitations.

We know that myocarditis and pericarditis are much more common with COVID-19 infection and damage to the heart is frequently severe after infection. The benefits of protection against COVID-19 far outweigh the risks from these rare and transient side effects.

Up-to-date information about Pfizer Comirnaty can be found in the Consumer Medicine Information (for consumers) and Product Information (for health professionals).

Useful links

ATAGI statement regarding COVID-19 vaccines in the setting of transmission of the Delta variant of concern – 2 August 2021

ATAGI statement regarding vaccination of adolescents aged 12–15 years – 2 August 2021

Top 3 COVID-19 vaccine questions – Vaccine eligibility and availability, long COVID syndrome, and the latest ATAGI advice – 30 July 2021

ATAGI update following weekly COVID-19 meeting – 28 July 2021

Latest COVID-19 weekly surveillance in NSW – 2 August 2021

Coronavirus (COVID-19) case numbers and statistics

Australia’s COVID-19 vaccine rollout

COVID-19 vaccines: Frequently asked questions – 15 July 2021

COVID vaccines – is it true? 14 July 2021

TGA COVID-19 vaccines hub

Australian Government Department of Health COVID-19 vaccines hub

AusVaxSafety (active surveillance activities and information) 

COVID-19 vaccine symptom checker

Database of Adverse Event Notifications (DAEN)

Advice on COVID-19 vaccination during pregnancy – 9 June 2021

Comirnaty vaccine – phase III clinical trial